Condensed consolidated statements of comprehensive income (loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net (loss) income including non-controlling interests	$ (31,985)	$ 39,827	$ (21,602)	$ 71,466
Other comprehensive income (loss), net:
Foreign currency translation adjustments	249	103	(360)	157
Total other comprehensive income, net	249	103	(360)	157
Total comprehensive (loss) income including non-controlling interests	(31,736)	39,930	(21,962)	71,623
Less: total comprehensive (loss) income attributable to non-controlling interests	(2,808)	4,983	(1,032)	9,213
Total comprehensive (loss) income attributable to Planet Fitness, Inc.	$ (28,928)	$ 34,947	$ (20,930)	$ 62,410